Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
  • H01L21/50—Assembly of semiconductor devices using processes or apparatus not provided for in a single one of the subgroups H01L21/06 - H01L21/326, e.g. sealing of a cap to a base of a container
  • H01L21/56—Encapsulations, e.g. encapsulation layers, coatings
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
  • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
  • H03H9/02—Details
  • H03H9/05—Holders; Supports
  • H03H9/10—Mounting in enclosures
  • H03H9/1064—Mounting in enclosures for surface acoustic wave [SAW] devices
  • H03H9/1071—Mounting in enclosures for surface acoustic wave [SAW] devices the enclosure being defined by a frame built on a substrate and a cap, the frame having no mechanical contact with the SAW device
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
  • H01L21/50—Assembly of semiconductor devices using processes or apparatus not provided for in a single one of the subgroups H01L21/06 - H01L21/326, e.g. sealing of a cap to a base of a container
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
  • H01L2924/15—Details of package parts other than the semiconductor or other solid state devices to be connected
  • H01L2924/161—Cap
  • H01L2924/162—Disposition
  • H01L2924/16235—Connecting to a semiconductor or solid-state bodies, i.e. cap-to-chip

Definitions

• This cover can serve as protection against external influences in the further manufacturing process, or it can form the basis for certain housing technologies.
• a cover can provide mechanical protection against scratches and impacts, hermetic protection against media used in the further processing method or protection against contamination, in particular against the conductive particles which are particularly troublesome in the case of miniaturized components.
• the housing can be completed on the basis of this cover, for example by casting with resin, molding with plastic, installation in a further housing, etc.
• surface acoustic wave components have particularly sensitive component structures, which can include interdigital transducers and reflectors formed from finely structured conductor tracks.
• Both the frame structure and the cover layer are preferably produced from photoresist material and in particular from photoresist films. For this purpose, they are laminated over the entire surface, exposed using a mask and developed. These steps must be carried out separately for the frame structure and cover layer. Overall, the process is relatively complex and requires a large number of process steps.
• the method according to the invention is based on a two-part encapsulation, namely a frame structure enclosing the component structures and a roof structure seated thereon.
• a liquid reactive resin which can be subsequently hardened is used both for the frame structures and for the roof structures.
• the second reaction resin layer is then over the auxiliary film structured applied.
• the areas of the auxiliary film which are exposed outside the frame structures or between the roof structures are removed, preferably by dissolving them with a solvent or by treating them with a plasma.
• a UV-curable reaction resin is used for the second reaction resin layer, which is still exposed, developed and hardened after application over the entire surface.
• the spin coating of the liquid reactive resins is a simple and easily controllable process step that is easier to carry out than the lamination of resist films and that is generally less expensive.
• the second reaction resin layer provided for the roof structure can then be applied in a desired thickness, which ensures sufficient mechanical stability for the encapsulation. It is then not necessary to apply additional layers over this roof structure.
• the imagewise exposure of the first and second reaction resin layers can be carried out by scanning with a laser, in particular with a UV laser. This has the advantage that the process can be adapted to varying component structures in a simple manner and that photomasks for the exposure process do not have to be produced in a complex manner.
• further component structures can also be produced, in particular damping structures in surface wave components.
• damping structures in surface wave components it is advantageous if the material of the
• Reaction resin layer is acoustically adapted, i.e. a has suitable hardness and a suitable modulus of elasticity.
• reaction resin layers are preferably developed with liquid developer, depending on the resin system used, with organic solvents or aqueous-alkaline.
• the structured second reaction resin layer is produced by structured printing on the auxiliary film in the area above the frame structures and hardening.
• Screen and stencil printing are suitable as structuring printing processes. Printing is not critical because of the auxiliary film, even with small structural dimensions of the component structures, since only the frame structures need to be covered with the second reactive resin layer. The printing accuracy of the printing processes mentioned is sufficient for this, even if this printing process is not suitable for producing the first reaction resin layer.
• a thin plastic film and in particular a thin thermoplastic film can be used as the auxiliary film. This has the advantage that it can be easily opened and thus creates a flat cover over the frame structures. Furthermore, the plastic film can be easily connected to the frame structures, for example by gluing, melting or welding.
• the material for the plastic film can be selected so that it can be easily removed again. In particular, it can be readily soluble in a solvent that can be used to remove the plastic film in the areas between the frame structures that are not intended to be covered by the encapsulation. A correspondingly thin plastic film can also be easily removed in a plasma, in particular in an oxygen-containing plasma.
• the thickness of the second reaction resin layer is selected sufficiently to provide sufficient resistance to the dissolution that also acts on the second reaction resin layer during this removal process.
• Polyamide, PET or polycarbonate films are particularly suitable as the material for the plastic film.
• the thickness of the plastic film is chosen so that it is as thin as possible on the one hand, but on the other hand is still sufficiently load-bearing to support the second reaction resin layer without excessive bending. Film thicknesses in the region of 1 ⁇ m are usually sufficient. However, thicker films up to approx. 20 ⁇ m or thinner films can also be used, in particular films with a thickness of 0.5 to 5 ⁇ m.
• FIGS. 1 to 8 use schematic cross sections through a component to be encapsulated to show different process stages in the production of the encapsulation.
• Figure 9 shows the component during a process stage in a schematic plan view.
• FIG. 1 shows a piezoelectric substrate 1, for example a wafer made of lithium tantalate or
• Lithium niobate Lithium niobate.
• Various component structures are now applied to the surface of the substrate 1, in particular electrically conductive structures, for example a metallization made of aluminum. Only parts of this metallization are shown schematically in FIG. 1, namely the sensitive component structures 2, which are arranged on a wafer, but can belong to different components.
• a light-sensitive reactive resin layer 3 is now spun onto the substrate 1 over the entire area of the component structures 2, for example in a thickness of approximately 50 ⁇ m. The thickness of the reaction resin layer 3 is chosen so that it exceeds the thickness of the component structures 2 so that the height difference between the upper edge of the component structures 2 and the reaction resin layer 3 ensures a safe distance for covering the component structures 2.
• a cationically initiated, non-curable and solvent-free epoxy resin which can be cured under UV radiation, is preferably applied as the reaction resin.
• this reaction resin also contains a photoinitiator or a photoinitiator system which is adapted to the exposure source.
• a photoinitiator or a photoinitiator system which is adapted to the exposure source.
• Such epoxy resins are described, for example, in DE-A 44 43 946, to which reference is made in full here.
• the reaction resin can also contain additives which are preferably basic in nature and can be selected from the group consisting of salt-like hydroxides or organic amines.
• Reaction resin layer 3 exposed and at least hardened.
• the exposure ensures a solubility gradient between exposed areas 5 and unexposed areas of the first reaction resin layer 3, which allows development using a developer solution.
• Figure 3 shows the component after development.
• the exposed areas 6 of the original first reaction resin layer 3 which remain after development form closed frame structures 6 which enclose the sensitive component structures 2. Possibly. a complete hardening of the frame structures 6, possibly only hardened by the UN laser, can take place at this process stage by briefly increasing the temperature. Complete curing can also be done before development.
• a thin plastic film 7 is now stretched over the frame structures 6 such that it lies tightly on the frame structures 6.
• the plastic film 7 used as the auxiliary film is preferably stretched over the entire substrate 1.
• Figure 4 shows the arrangement after this process step.
• An adhesive connection between the film 7 and the frame structures 6 is brought about by heating, using a film coated with adhesive, by laser or friction welding or similar measures.
• a layer 8 of a likewise light-sensitive liquid reaction resin is then spun onto the entire surface of the auxiliary film 7.
• the same resin as that for the first reaction resin layer is used.
• the thickness of this second reaction resin layer 8 is chosen so that it lies considerably above the thickness of the plastic film 7.
• Figure 5 shows the arrangement after this step.
• a structuring exposure for producing hardened areas 9 is now generated, which is also carried out by scanning UV laser radiation, analogously to the exposure of the first reactive resin layer 3.
• the hardened areas 9 are arranged so that they belong to the Form frame structures 6 that fit and terminate with their outer circumference (see FIG. 6).
• the areas of the plastic film 7 that are not covered by the roof structures 10 are removed, for example by a brief ashing treatment in a suitable, e.g. oxygen-containing plasma.
• a brief ashing treatment in a suitable, e.g. oxygen-containing plasma.
• the exposed, uncovered areas of the plastic film 7 are completely removed.
• a partial layer removal of the roof structures 10 takes place.
• FIG. 8 shows the completely encapsulated component structures 2, the
• Encapsulation consists of the frame structure 6 and the roof structure 10 with residues of the auxiliary film 11 lying in between.
• the component structures 2 are now hermetically sealed and, for example, protected against further aggressive process steps. It is also possible to separate the components at this stage by dividing the substrate 6 between the component structures or the encapsulations, which can be done, for example, by sawing.
• FIG. 9 shows a schematic top view of the arrangement of the frame structures 6 around the sensitive component structures 2, which are shown here only schematically in the form of a meander.
• the sensitive component structures can be connected to electrical connection surfaces 12 on the substrate 1 via conductor tracks.
• the frame structure 6 is then arranged such that the sensitive component structures 2 are enclosed, which ⁇ tt l- 1 H o L ⁇ o L ⁇ O Ul ⁇ ⁇ _ Cß Cd ⁇ tr O ⁇ d N CL ⁇ W tö CL ⁇ ? JD ⁇ ⁇ Jö MN
• d SD d CL d ⁇ P- P, 03 P- dd ⁇ > P- ⁇ rt ⁇ i rt) CL (D H- P- LQ ' rt) fD 03 ⁇ (t ) CL d rt d 03 ti ⁇ Cd 3 3 ⁇ P- 3 Q ⁇ d ⁇ tr rt rt d 03 P- 0 fl)? h
• P- SD Pf d 0J fD CTJ d p d ⁇ X ⁇ 03 03 ⁇ P- LQ 0 p; tr rT d r rt) 9> P P- d d i SD hj P- fD T ⁇ tr tr rt) d ⁇

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Computer Hardware Design (AREA)
• Condensed Matter Physics & Semiconductors (AREA)
• General Physics & Mathematics (AREA)
• Manufacturing & Machinery (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Power Engineering (AREA)
• Acoustics & Sound (AREA)
• Encapsulation Of And Coatings For Semiconductor Or Solid State Devices (AREA)
• Micromachines (AREA)
• Structures Or Materials For Encapsulating Or Coating Semiconductor Devices Or Solid State Devices (AREA)
• Photosensitive Polymer And Photoresist Processing (AREA)
• Electrostatic, Electromagnetic, Magneto- Strictive, And Variable-Resistance Transducers (AREA)
• Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=7630816

Family Applications (1)

Country Status (8)

Cited By (3)

Families Citing this family (15)

Citations (5)

Family Cites Families (5)

• 2000
  • 2000-02-14 DE DE10006446A patent/DE10006446A1/de not_active Withdrawn
• 2001
  • 2001-02-02 US US10/203,710 patent/US6984421B2/en not_active Expired - Lifetime
  • 2001-02-02 EP EP01919124A patent/EP1256128B1/de not_active Expired - Lifetime
  • 2001-02-02 KR KR1020027010114A patent/KR100742435B1/ko active IP Right Grant
  • 2001-02-02 CN CNB018050441A patent/CN1205660C/zh not_active Expired - Lifetime
  • 2001-02-02 WO PCT/DE2001/000404 patent/WO2001059827A1/de active Application Filing
  • 2001-02-02 CA CA002399417A patent/CA2399417A1/en not_active Abandoned
  • 2001-02-02 JP JP2001559053A patent/JP4970684B2/ja not_active Expired - Lifetime

Patent Citations (6)

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